Custom Radius Arms (1 Viewer)

[Nay]

So if the arms were designed moving the front bushing to above the axle, would there be any benefit in keeping the front bushing for on road manners? Same basics as the hitch pin mod, a pin you can pull to eliminate that link. Basically making it a 5 link on road, and a 4 link (in two planes) off.

Also, is it better to move the front link on one of the arms above the axle, or the rear link? For additional flex would you want the two links closer together or further apart?

No benefit and you'd be back to the 'skinny arm' requirement. The reality is that in order to get a y-link to flex you need a larger bushing that can deflect more than the stock 80 stuff and I don't think there is a good way around this. You want the front bushing moved above the axle with a decent amount of spacing between the upper and lower mounts.

Take a look at the Jeep radius arm stuff such as Rubicon express. That's pretty much what you are looking at in terms of design and in fact I'd use a Jeep aftermarket solution as that will provide you access to factory and/or aftermarket bushings.

Now what Jeep is doing is utilizing the existing four-link mounts, but it works well and is proven design with those larger bushings and I think the easiest approach is to mimic that setup.

 

[Ebag333]

No benefit and you'd be back to the 'skinny arm' requirement.

What are you talking about here? The extra link for on road performance or moving the lower rear link (instead of the lower front link)?

Two seperate questions, and you're not specifying which one you're referring to. Throw me a frickin' bone here.

 

[Ebag333]

Take a look at the Jeep radius arm stuff such as Rubicon express. That's pretty much what you are looking at in terms of design and in fact I'd use a Jeep aftermarket solution as that will provide you access to factory and/or aftermarket bushings.

Something like this?

Two concerns about putting a Jeep product on an 80. One, weight. (4k-5k lb design vs 6k-7k lb design.) Two, putting anything labelled "Jeep" on a Toyota!

 

[Walking Eagle]

What are you talking about here? The extra link for on road performance or moving the lower rear link (instead of the lower front link)?

Two seperate questions, and you're not specifying which one you're referring to. Throw me a frickin' bone here.

Something like this?

Two concerns about putting a Jeep product on an 80. One, weight. (4k-5k lb design vs 6k-7k lb design.) Two, putting anything labelled "Jeep" on a Toyota!

The skinny arm because when you've got the pin pulled from the 'extra link' it has to move in and out of the bracket on the axle.

Check out Jodo's build - he used rubicon express stuff I believe, and went with the theory that a 4 door loaded jeep is getting pretty close to 6k lbs.

 

[Ebag333]

The skinny arm because when you've got the pin pulled from the 'extra link' it has to move in and out of the bracket on the axle.

'Kay, that makes sense.

But the real question is, forgetting about off-road capability, would the stability of an extra link be worth it for on road manners? Basically retaining that front lower link for on road travel.

Check out Jodo's build - he used rubicon express stuff I believe, and went with the theory that a 4 door loaded jeep is getting pretty close to 6k lbs.

I'm sure that the RE stuff is overbuilt and all, but looking at pics they do not seem as beefy as stock 80 arms. Additionally, Slee had a few failures with arms designed in the same manner (welded together) as the RE arm pictured above, seems a single piece arm would be much more desirable.

Even if a 4 door loaded jeep is close to 6k lbs, I'm starting at 6300 lbs basically empty (two passengers, no gear to speak of). Once fully loaded could easily be pushing 7k lbs, and if hauling a heavy "work" load could easily break 7k lbs.

Even if the RE arms are designed with a pretty good sized safety margin, it was as safety margin for a significantly lighter vehicle.

Basically, I wouldn't trust it for a DD. For off road only, yeah, sure.

 

[Walking Eagle]

'Kay, that makes sense.

But the real question is, forgetting about off-road capability, would the stability of an extra link be worth it for on road manners? Basically retaining that front lower link for on road travel.




I'm sure that the RE stuff is overbuilt and all, but looking at pics they do not seem as beefy as stock 80 arms. Additionally, Slee had a few failures with arms designed in the same manner (welded together) as the RE arm pictured above, seems a single piece arm would be much more desirable.

Even if a 4 door loaded jeep is close to 6k lbs, I'm starting at 6300 lbs basically empty (two passengers, no gear to speak of). Once fully loaded could easily be pushing 7k lbs, and if hauling a heavy "work" load could easily break 7k lbs.

Even if the RE arms are designed with a pretty good sized safety margin, it was as safety margin for a significantly lighter vehicle.

Basically, I wouldn't trust it for a DD. For off road only, yeah, sure.

I wouldn't let failed Slee's arms prevent me from going this road. There are a 100+ times more vehicles on the road with this design than all of his arm designs put together. Not dissing him, just saying there is a bunch of proof that a tube radius arm is fine. Besides, weren't his still under the axle front and rear? That's a different animal all together than a y-radius arm, so it's not even a valid comparison.

I'm not pushing RE stuff - just tell'n ya' what Jodo's logic was. Maybe he used gran cherokee ones? Somehow he logic'd himself into it. Don't believe he's had any issues.

You could build your own, and if you did it right they would be strong enough. Or, if you want something pre-made, I'm sure there is a y-link set-up for ford superduties out there somewhere. I know you can get radius arm suspension for them, but don't know how well they flex. I think part of the advantage of the RE links is that it's two piece with an extra bushing (compared to other radius arms) - I have to think that extra bushing and the angle it's on helps with binding.

 

[Ebag333]

I wouldn't let failed Slee's arms prevent me from going this road. There are a 100+ times more vehicles on the road with this design than all of his arm designs put together. Not dissing him, just saying there is a bunch of proof that a tube radius arm is fine. Besides, weren't his still under the axle front and rear? That's a different animal all together than a y-radius arm, so it's not even a valid comparison.

Indeed his were more the stock design, which we all know causes more stress than a 3 link or even moving the front link. And I don't have a problem with welded stuff per say, just pointing out that someone already went that road and had issues with it. And given the amount of damage that will happen should it fail....

I'm not pushing RE stuff - just tell'n ya' what Jodo's logic was. Maybe he used gran cherokee ones? Somehow he logic'd himself into it. Don't believe he's had any issues.

Jodo's build is sweet, and a very clever design. But from the start I had concerns about the weight issue, and still have those today. I'm sure he's running them just fine, but for my purpose I absolutely want something that will not fail. Closest serious trail to me is about 6 hours away (either direction, north or south) so I have to spend a lot of time on pavement to go wheeling.

You could build your own, and if you did it right they would be strong enough. Or, if you want something pre-made, I'm sure there is a y-link set-up for ford superduties out there somewhere. I know you can get radius arm suspension for them, but don't know how well they flex. I think part of the advantage of the RE links is that it's two piece with an extra bushing (compared to other radius arms) - I have to think that extra bushing and the angle it's on helps with binding.

Noticed the extra bushing, wonder how much flex that actually adds. Maybe they're using poly bushings that have less flex than our OEM rubber, so need the extra bushing.

 

[Walking Eagle]

just pointing out that someone already went that road and had issues with it. And given the amount of damage that will happen should it fail....

Nope, Slee did a different design, different road, different issues.

 

[Nay]

Something like this?

Two concerns about putting a Jeep product on an 80. One, weight. (4k-5k lb design vs 6k-7k lb design.) Two, putting anything labelled "Jeep" on a Toyota!

Yep, that's what I'm talking about. You aren't going to have a problem with the DOM wall dimensions of those setups.

As for using Jeep aftermarket stuff...........if it works, it works. So many Toyota owners running around on busted ass stuff because they refuse to adopt proven solutions simply because they don't say Toyota

 

[jvazquez53]

The skinny arm because when you've got the pin pulled from the 'extra link' it has to move in and out of the bracket on the axle.

Check out Jodo's build - he used rubicon express stuff I believe, and went with the theory that a 4 door loaded jeep is getting pretty close to 6k lbs.

Boy that thing looks flimsy, compared to Toyota!

 

[Nay]

I'm sure that the RE stuff is overbuilt and all, but looking at pics they do not seem as beefy as stock 80 arms.

They aren't cast like the 80 front arms - it's DOM. I'd rather 'slide' on a cast 80 series arm with it's curved shape, personally - that's one of the best attributes of our factory setup.

However, those Jeep arms are magnitudes beefier than the rear control arms that came from the factory on the 80. You aren't going to get a failure due to DOM wall thickness for certain.

 

[Ebag333]

They aren't cast like the 80 front arms - it's DOM. I'd rather 'slide' on a cast 80 series arm with it's curved shape, personally - that's one of the best attributes of our factory setup.

However, those Jeep arms are magnitudes beefier than the rear control arms that came from the factory on the 80. You aren't going to get a failure due to DOM wall thickness for certain.

Not worried about the DOM wall failing. Weld...more of a concern.

Agreed that they are beefier than the rear control arms. Or at least they were until I got a hold of mine.

Difference is, if I completely snap a lower rear LCA (and lets face it, if I break an upper rear LCA I have other issues!) the axle will be seriously messed up but even at speed can likely drive out of the situation (well enough to pull over). There are three other arms to hold the axle in place.

If I break a front LCA....I'm likely screwed, especially at speed.

 

[Nay]

Not worried about the DOM wall failing. Weld...more of a concern.

Agreed that they are beefier than the rear control arms. Or at least they were until I got a hold of mine.

Difference is, if I completely snap a lower rear LCA (and lets face it, if I break an upper rear LCA I have other issues!) the axle will be seriously messed up but even at speed can likely drive out of the situation (well enough to pull over). There are three other arms to hold the axle in place.

If I break a front LCA....I'm likely screwed, especially at speed.

The arm in the pic above ins't something I would use due to the bend in the main arm, which is being done for the obvious reason I pointed out earlier: the loss of clearance. But a straight piece of DOM with a welded eye mount isn't a realistic failure point in this design as it isn't subjected to much stress when used with a larger bushing.

I'd be a lot more worried about the axle mounts on my 80 series failing due to the stress they consistently face in the stock design when used heavily offroad.

 

[-Spike-]

I'd be a lot more worried about the axle mounts on my 80 series failing due to the stress they consistently face in the stock design when used heavily offroad.

The stresses on arms when flexing using the stock mounts scare me. The twisting forces are intense.

 

[Pin_Head]

The failure of some of the welded tube arms doesn't necessarily indicate that the design is inadequate. The failures I have seen pictures of were clearly due to inadequate welding by someone that was not trained in welding. There was no penetration to the root of the tube and even if they were filet welds, the width of the weld face was clearly inadequate. One of the cases where you can see a poorly engineered weld just by looking at it. If you have a professional welding them you wouldn't have the problems shown in the picture. The guy that "welded" them was glue gunning with metal.

 

[Ebag333]

I can see this is something I'm not going to win on.

Regardless, a run of cast arms is likely to be far cheaper than machined or assembled (welded) arms, if you can get enough people interested. And it looks like the number of people interested is actually reasonably small.

 

[LandCruiserPhil]

The failure of some of the welded tube arms doesn't necessarily indicate that the design is inadequate. The failures I have seen pictures of were clearly due to inadequate welding by someone that was not trained in welding. There was no penetration to the root of the tube and even if they were filet welds, the width of the weld face was clearly inadequate. One of the cases where you can see a poorly engineered weld just by looking at it. If you have a professional welding them you wouldn't have the problems shown in the picture. The guy that "welded" them was glue gunning with metal.

I thought that arm looked familiar...here is closer view.
FWIW it was a wristed AO arm

 

[Walking Eagle]

Not worried about the DOM wall failing. Weld...more of a concern.

If welded properly, the metal should fail before the weld does.

The arm in the pic above ins't something I would use due to the bend in the main arm, which is being done for the obvious reason I pointed out earlier: the loss of clearance. But a straight piece of DOM with a welded eye mount isn't a realistic failure point in this design as it isn't subjected to much stress when used with a larger bushing.

If a person was really worried about weld strength there are things that can be done. You can take a piece of flat steel and bend it aroung the eye mount and run it back along the tube several inches and weld all along the seam. Reinforces it cause it's more metal, and it gives you more weld area. Not my idea, just seen it done before.

Alternatively, if you make the main arm straight like Nay is saying, get rid of welding it alltogether. Just run thick wall dom, tap the end of it, and run some forged threaded ends like Johny Joints or one of the many other ones out there. They even have billet ones now. The only reason I say make it straight is it'd be hard to get someone to bend .5" wall DOM. If you make the other part of the arm straight too the only welding on the whole deal is the bracket on the main arm. That can be made with a really long base to give plenty of weld length (the red areas are weld).

A side bennefit of this construction is you can grease the threads on the frame end of the link, and leave the jamb nut loose - makes the arm that much easier to rotate (flex) from what I've read. It's not like the link is going to unscrew itself (it can't).

There are several advantages over casting some arms - first it's going to be cheaper than building a tool. Second, with the adjustable end joints you can dial in the centering of your wheel in the well. Third, with the adjustable second link you now have the ability to adjust caster

So, to recap - you end up with a main link 2"x.5" DOM tapped - that is not going to fail. You have huge weld length, so not likely to fail. If a weld does fail, it's not likely going to fail on both sides at once, and if one side does fail you've just created a poor man's three link.

As far as trying to stick with the one in front one behind like stock to maintain some stability on road - I say throw a bigger front swaybar on with disconnects and call it good.

 

[Ebag333]

As far as trying to stick with the one in front one behind like stock to maintain some stability on road - I say throw a bigger front swaybar on with disconnects and call it good.

Some good stuff here.

The problem is, if you're moving both front mounts behind and above the axle, you've just recreated Bronco style arms. Which have a problem with binding on flex. Which is why they wrist them to eliminate the bind.

The whole idea of having one mount forward, one up is to have two different planes at play. If you move both front mounts, you're back to a single plane, which will bind.


That's why there's the extra bushing in the Rubicon Express arms (and yours), to help eliminate that bind. But then you get the extra slop that the bushing adds, which a bigger sway bar may or may not be able to control. (Plus replacing the sway bar adds expense to the whole endeavor.)


That's why I like the arms that Nay brought up (which I've seen before, but had completely forgotten about). By moving only one of the mounts you greatly reduce the binding that's in the stock axle, but get to keep the stability of a 4 link with solid arms.

 

[Walking Eagle]

well, if you just want to gain flex by doing one arm, certainly can do tube (attached is a superduty radius arm, I think it's at least equivalent to an 80 series) and welded. And can do it cheaper than casting - if it was cheaper I'm sure someon out there would be doing it for superduties and there are many more of them around than 80 series. Course, then you get no castor adjustment, no length adjust.

If you're looking to do both arms, and cast them and sell them, even to 10 people, you've got patient issues with Superior Engineering.

I still say as far as simplicity, to gain flex, caster adjustment, ect., without the complexity of a 3-link, Y-radius arm is the way to go - I really doubt you'll find that much more slop in the system, and you can tune that by the choice of bushing as well.

Something like this

One Up Offroad Adjustable Link Arms - 2005-2011 F250/350/450 4wd - Truck Toyz Store

is so much cheaper than investing in casting / forging arms - even if you add the cost of a heavier sway bar (which I'm not convinced you'd need).